One type of proposed prior art gas detector employs capacitors having a solid electrolyte, i.e., ionic, dielectrics, such as lanthanum fluoride (LaF.sub.3). In the past, such gas detectors have been operated in the DC potentiometric method wherein a DC voltage applied between electrodes of the capacitor is modified as a function of the type and amount of gas incident on the dielectric. The DC potentiometric method, however, has the disadvantage of drift in the measuring apparatus and offset due to a polarizing effect of the DC voltage applied to the electrodes. These phenomena have a tendency to adversely affect the accuracy of quantitative and qualitative readings from the detector.
Certain types of the proposed prior art gas detectors employing solid electrolyte dielectrics have required the dielectric to operate at an elevated temperature. This disadvantage, which does not occur with lanthanum fluoride, decreases the efficiency of the detector because of the power required to supply the heat to elevate the dielectric temperature. The prior art gas detection apparatus and methods employing capacitors with solid electrolyte dielectrics have only generally been able to detect a very limited number of gases.
It is desirable to detect humidity of an ambient atmosphere through the use of capacitors having solid electrolyte dielectrics. However, prior art structures employing capacitors with solid electrolyte dielectrics for humidity detection have been plagued with inaccuracies because ambient environment temperature changes affect the capacitor impedance.
It is, accordingly, an object of the present invention to provide a new and improved method of and apparatus for detecting gases through the use of capacitors having solid electrolyte, i.e., ionic, dielectrics.
Another object of the present invention is to provide a new and improved gas detecting method and apparatus employing a capacitor having a solid electrolyte dielectric which is responsive to a relatively large number of gases, to provide accurate quantitative and qualitative information regarding said gases.
A further object of the present invention is to provide a new improved gas detecting method and apparatus employing a capacitor with a solid electrolyte dielectric capable of accurate quantitative and qualitative analyses at room temperature.
A further object of the invention is to provide a new and improved temperature and/or humidity detector that is accurate over a wide range of temperatures and which employs a capacitor having a solid electrolyte dielectric.
An additional object of the invention is to provide a new and improved method of and apparatus for accurately providing quantitative and qualitative information of ambient gases, wherein a capacitor employing a solid electrolyte dielectric is operated at room temperature.